Investigation of the Blockage Correction to Improve the Accuracy of Taylor’s Low-Speed Wind Tunnel

Wind tunnels are equipment that allows researchers to experimentally study the wind flow around a test model and the forces and moments acting on it. A wind tunnel aims to obtain aerodynamic data such as force and momentum coefficients, test various configurations, look at high lift devices, reduce drag, and develop simulators before the first flight. While the test model is placed inside the test section, there is an interaction (interference) between the model and the walls of the wind tunnel test section and the wind flow. This interaction affects the accuracy of data reading of the wind tunnel because of factors that might affect these readings. One of the significant factors is blockage. A blockage in the wind tunnel might increase the drag and lift coefficients, causing the results to differ from their real value. A lot of studies have been done previously to solve the wind tunnel blockage effect. However, most of the blockage correction method researches only worked with one type of shape, such as streamline, blunt, or bluff shaped bodies. This paper deals with two different shapes with different sizes for each to investigate and assess the effect of the shape and size of the test model on the accuracy of wind tunnel testing. Streamlined and blunted shapes are considered for this study. These two shapes were considered because the streamlined shape is a lift generating shape, whereas the blunted shape is a non-lift generating shape. The aim is to study how these shapes with different characteristics affect the wind tunnel readings. Wind tunnel tests will be conducted with the three different sizes for each shape to determine the coefficient of aerodynamic forces for all the models. Different sizes provide different blockage ratios during wind tunnel testing. Therefore, different sizes are considered to study how the blockage ratio affect the wind tunnel reading. In the present work, different correction methods will be applied in order to find the correction coefficient. Besides, CFD simulation also will be performed using ANSYS Fluent software. After all the tests and simulations are done, a detailed comparison of numerical and experimental results will be carried out to determine the most suitable blockage correction method for the chosen model.